Cant believe that my first post on a knives forum is going to be about pants
Anyway my favourites are Arctyrex Spotter Pants which are super comfortable due to the articulated design, extremely hard wearing (climbing pants). They also look great IMHO. You can also buy the shorts version which are equally amazing:
http://www.arcteryx.com/Product.aspx?EN/Mens/Spotter-Pant
Kuhl are also pretty good, hard wearing too but I personally prefer the Arctyrex fit and look:
http://www.backcountry.com/kuhl-crag-runner-pant-mens
I have worn the Arctyrex in 50c Climbing in Italy and they handled the temperatures surprisingly well. Wore then in the Scottish highland's to -15 without thermals or waterproof layers and they were fine too.